Starting on the 19th of September 2020, 50% of all trading fees are distributed to veCRV holders. This is the result of a community-led proposal to align incentives between liquidity providers and governance participants (veCRV holders).
Collected fees will be used to buy 3CRV (LP token for 3Pool) and distribute them to veCRV holders. This currently represents over $15M in trading fees per year. veCRV stands for vote escrowed $CRV, they are $CRV vote locked in the Curve DAO.